Q. 263.5( 2 Votes )

# A string of negligible thickness is wrapped several times around a cylinder kept on a rough horizontal surface. A man standing at a distance *l* from the cylinder holds one end of the string and pulls the cylinder towards him (figure 10-Q4). There is no slipping anywhere. The length of the string passed through the hand of the man while the cylinder reaches his hands is

A. *l*

B. 2*l*

C. 3*l*

D. 4*l*

Answer :

The cylinder needs to reach the person i.e. To travel a total of distance L. Let us assume the radius to be r.

We know that the length of an arc is

Hence

So to cover the distance L it needs extra arc length of,

Hence it covers extra L length.

So, the total length will be ,2L.

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